Pour remaining 1 tablespoon olive oil into skillet with onions over medium heat; cook steak roll in the onion mixture, turning steak until browned on all sides, 2 to 3 minutes per side. Add tomato sauce, sugar, and chopped tomato to the steak mixture; simmer over very low heat until steak is cooked through and sauce has slightly reduced, 1 to 1 1/2 hours.